olemus
UML:
olekumasina erijuht protokolli spetsifitseerimiseks
= a special case of state machine, applied to protocol specification

ülevaateid
https://d3s.mff.cuni.cz/legacy/~gergic/statecharts/uml15.html

https://www.site.uottawa.ca/~tcl/gradtheses/mnojoumian/ThesisFiles/FinalSpec/UML/15.3.6.html

https://docs.nomagic.com/display/MD2022xR1/Protocol+State+Machine+diagram